Pulmonary Defense Mechanisms

Question 1

IgA is translocated by

Answer 1

Airway epithelium

Question 2

First line of defense in alveoli and function

Answer 2

Macrophages- M2 residents
Maintain tolerance
Typically immunosuppressive- secrete IL-10, TGF-b
Can also respond in inflammatory M1 manner if there is threat

Question 3

Surfactant proteins

Answer 3

SPA/SPD
Synthesized by type II alveolar and Clara cells
Bind pathogens, suppress microbial growth, damage bacterial membranes and modulate phagocytosis

Question 4

Immunoglobulins of alveolar space

Answer 4

IgA and IgG

IgA does not promote inflammation

Question 5

Nonimmune opsonins

Answer 5

Surfactant, fibronectin, MBL and CRP

Question 6

Recruitment of leukocytes

Answer 6

IL-1 and TNF increase expression of P&E selectin expression
Neutrophils arrive in hours (IL-8), macrophages in days (CCR2)

Question 7

Chronic inflammatory response

Answer 7

Infiltration of activated T cells and M1 macrophages
Mucus hypersecretion
Substantial tissue remodeling leading to fibrosis, emphysema

Question 8

Type I hypersensitivity (atopic response)- early response

Answer 8

Cross linking of IgE
Degranulation of Mast cells:
Secrete IL-4 for type 2T helper cells
Also secrete histamine and leukotrienes 
Secrete IL-5 as well activating eosinophils
Sneezing/rhinorrhea/congestion

Question 9

Late phase type I hypersensitivity (atopic response)

Answer 9

Influx and activation of eosinophils, neutrophils, basophils and Th2
10x increase in mast cells in area
Eosinophils release inflammatory mediators
Th2 release IL-4/5/13

Question 10

Leukotrienes

Answer 10

C4/D4/E4 drive tissue remodeling, induce bronchospasm, vascular permeability and mucus production
Recruit smooth muscle cells and fibroblasts

Question 11

Prostaglandins

Answer 11

D2, E2, F2 induce bronchospasm and vasodilation

Recruit smooth muscle cells and fibroblasts

Question 12

Bronchial asthma treatments

Answer 12

Corticosteroids
Leukotriene antagonist- relax bronchial smooth muscle and reduce inflammation
Phosphodiesterase inhibitors- relax bronchial smooth muscle

Question 13

Cromolyn

Answer 13

Drug that inhibits mast cell degranulation

Question 14

What mediates inflammation in COPD

Answer 14

Th17 cells produce IL-17 and IL-22
IL-17 induces airway epithelial cells to secrete IL-8, attracting neutrophils
CD8 is way more of a lymphocyte mediated disease as opposed to asthma

Question 15

Asthma vs COPD progression

Answer 15

Asthma- allergens activate epithelial cells and mast cells leading to CD4 and eosinophil activation and eventual bronchoconstriction
COPD - smoking activates alveolar macrophages and epithelial cells, TH17 cells are activated leading to neutrophils invasion as well. CD8+ T-cells get recruited as well - Irreversible process, unlike asthma

Question 16

Ventilator associated lung injury

Answer 16

Iatrogenic
Physical damage- over inflation and mechanical stress
Biodamage- hyper oxygenation, free radical production, influx of neutrophils and netosis leading to platelet clot formation

Question 17

Vaping associated lung injury

Answer 17

Present with acute respiratory distress syndrome
Vaping THC can cause lipoid pneumonia due to vitamin E acetate inhalation
Lung is coated with lipids